One Is a Lonely Number (1972) was also supposed to be the next hit for director Mel Stuart, fresh off his triumph with Willy Wonka & the Chocolate Factory (1971) and two previous successful comedies. One Is a Lonely Number (1972) received excellent reviews for both director and star. "This picture should propel Miss Van Devere toward stardom," Variety predicted. And "for those who may have missed something in Stuart's earlier comedies, this film will be a turning point." But perhaps because of the downbeat nature of the story, the film did not do well at the box office. MGM tried changing the title to Two is a Happy Number. It didn't help. Instead of waiting for the good reviews and the word of mouth to build an audience, the studio yanked the film, and it disappeared. However, Van Devere received a Golden Globe nomination for her performance.
First film role of any kind for Joe Spano, who was credited as Joseph Spano, and who portrayed Earl of Kent.
The Mission Pool where Amy works was built in 1916 and is still in use as of 2023. It is the only outdoor city-owned pool in San Francisco.
In 1975, Martin Scorsese's Alice Doesn't Live Here Anymore (1974), the story of a single mother rebuilding her life, won an Oscar® for Ellen Burstyn. A few years later, Paul Mazursky's An Unmarried Woman (1978), also a feminist tale of a woman rebounding from divorce, was a major hit. Yet both of those excellent films had happily-ever-after endings, and were less realistic and straightforward than One Is a Lonely Number (1972). From the perspective of 30-plus years later, the latter looks more and more like a film ahead of its time.